Intestinal Health Excellent Source of Soluble FiberHelps Maintain Regularity A Dietary Supplement Vegetarian Product Psyllium is a true dietary fiber, even though it is classified by some as a laxative or mucilaginous fiber, and is a convenient way to increase intake of dietary fiber because of its high mucilage content. This bulking agent swells considerably when added to liquid, which can help to support healthy gastrointestinal transit time. This bulking action and healthy transit time can play an important role in maintaining healthy gastrointestinal function.